Most of the models addressing in-medium hadron properties focus on vector mesons and in particular the short-lived \(\rho \) , which is ideally suited for experiments with dileptons.
For comprehensive overview on this topic we refer to excellent dedicated works [1]}, [2]}).
Below we want to shortly summarize the most important conclusions obtained from various hadronic models with emphasis on the model worked out by Rapp and Wambach, commonly used for comparisons with results from Heavy Ion collisions.
The model incorporates achievements worked-out by many other authors, which we briefly discuss below (for details see [1]}, [4]}).
The calculations in hadronic models are based on effective hadronic Lagrangians of \(\rho \)  interactions with mesons and baryons with vertices and coupling constants constrained by available experimental data.
Among them are: results on vector meson production in pion induced and photon induced reactions, photo-absorption and available decay widths of resonances to vector meson channels.
Medium effects on the mesons self energy are then obtained using many body theory.
For example, the main effects on the in-medium spectral function of \(\rho \)  meson are given via modifications of the pion loop in the \(\rho \)  meson self-energy term and via the direct interactions of \(\rho \)  meson with a resonance-nucleon hole (\(\rho -BN^{-1}\) ) and mesonic (\(\rho -M\) ) states.
The \(\rho -BN^{-1}\)  interactions are governed by baryonic resonances (including also hyperons) with significant couplings to (\(\rho ,N\) ) final states.
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